This invention relates to improvements in foam producing equipment. Embodiments have a wide field of application, with a particular utility in fire fighting on account of a unique capability in producing large quantities of a dense low moisture foam with an economical use of liquid detergent type solutions and compressed gas.
Foam producing apparatus as known heretofore, even as shown in applicant's own prior application for U.S. Letters Pat. Ser. No. 459,882, filed Apr. 11, 1974 for FOAM PRODUCING APPARATUS, now Pat. No. 3,979,326, dated Sept. 7, 1976 provides for a generally free rising foam to move through vertical stages the arrangement of which necessitates the use of a relatively large vertically extended container in order to properly develop the foam. In use of such apparatus provision must be made to prevent liquid separated in the upper portions of the container from interfering with and wetting the rising foam. Efforts in this direction have met with limited success although definite improvement was effected in the art by reason of applicant's own previous above identified invention.
A further problem that has been found in use of prior art apparatus for foaming purposes is that while such apparatus does in some instances effectively produce foam having a relatively low moisture content, the efficiency of such production, that is the volume of foam produced in relation to the quantity of liquid solution and compressed gas employed, has not been notably high. Nor does the normally produced foam have the degree of dryness to satisfy certain critical applications. It has been basically evident in use of prior art apparatus, moreover, that a large volume production of very dry foam with a relatively low consumption of liquid solution, a desirable and necessary objective where such apparatus is to be used to fight fires, has heretofore been difficult to achieve.